Potential human health risks of mercury-contaminated cassavas – Preliminary studies

The inevitable use of mercury (Hg) and the regular release of its waste into the ecosystem through artisanal and small-scale gold mining (ASGM) activities particularly, in developing countries such as Ghana require constant monitoring and evaluation of Hg contamination and its potential toxicities particularly, in samples such as food. This study evaluated the potential human health risks associated with total mercury (THg) and methylmercury (MeHg) levels of mercury-contaminated cassavas from farms in selected ASGM communities around Obuasi, Ghana. The THg and MeHg levels were evaluated using the direct Hg analyser, MA-3000 while the human health risk assessment was done using the USEPA risk assessment model. The estimated average daily intake for ingestion (eAvDI(ing)) (mg/kgbw/day) and the hazard quotient (HQ) for THg levels of the samples were above the USEPA reference values of 3 x 10−4 and 1, respectively. This means that residents ingest more Hg through consumption of cassava, hence long-term repeated exposures to the cassavas may be associated with detrimental human health effects in future. MeHg levels may not cause any human health effects due to eAvDI(ing) and HQ below 1 x 10−4 and 1, respectively. However, constant releases of mercury waste and subsequent bioaccumulation along the food chain can cause MeHg levels to increase with time above the USEPA acceptable daily intake. Such levels may be detrimental to human health. Therefore, there is the need for regular and strict monitoring of ASGM activities within the studied communities and other communities involved in ASGM to protect human health and preserve ecosystem integrity.